Synovial Cell Sarcoma

What is Synovial Cell Sarcoma?

Synovial sarcoma (SS) is a type of tumor that partly turns into a different type of cell, specifically, those that line certain parts of our body such as joints, tendons, or bursae. It is more frequently found in older kids and young adults. A key characteristic of synovial sarcoma is the presence of a change or ‘translocation’ in certain chromosomes, which is often tested for in the lab.

Synovial sarcoma is known for its aggressiveness, as it can easily spread to other parts of the body. Like other types of sarcoma affecting soft tissues in the body, the best approach to treat this condition is often to surgically remove the tumor making sure no microscopic cells are left behind. Additionally, radiation therapy around the time of surgery is a common part of the treatment. While the usefulness of chemotherapy before or after surgery is under debate for adults, it has become a regular part of treatment for children with this condition.

What Causes Synovial Cell Sarcoma?

In most cases of synovial sarcoma, which is over 90%, there’s a specific change in the patient’s genes. This involves the swapping of pieces between two genes, the SS18 gene located on chromosome 18 and one of several synovial sarcoma X (SSX) genes on chromosome X.

However, this type of sarcoma isn’t connected to any environmental or inherited factors, meaning it’s not something you get from exposure to certain substances or from your parents.

There are very rare instances where synovial sarcoma is triggered by radiation, but these cases are exceptionally uncommon according to medical literature.

Risk Factors and Frequency for Synovial Cell Sarcoma

Synovial sarcoma is a type of cancer that makes up about 10% of all soft tissue sarcomas. Each year in the US, there are between 800 and 1,000 new diagnoses. The total number of people living with this disease is roughly 2,129, making it a relatively rare condition.

While anyone can develop synovial sarcoma, it’s most common in teenagers and adults under 30, making it the most common type of sarcoma in this age group.

• Synovial sarcoma accounts for about 10% of all soft tissue sarcomas.
• Annually, 800 to 1,000 new cases are reported in the US.
• About 2,129 people have this disease at any given time.
• It is most frequently diagnosed in teenagers and young adults under 30.
• In this age group, it is the most common type of sarcoma.

Signs and Symptoms of Synovial Cell Sarcoma

Synovial sarcoma is a type of cancer that generally originates from deep tissues in arms and legs. However, it can also affect other parts like the chest, back, and neck. In some rare instances, it can show up in parts like the lungs, heart, gastrointestinal tract, and other organs. Usually, a hard-growing lump that can slightly move within the muscle (unless it’s attached to the bone or a band of connective tissue known as fascia) is spotted. Other than this, the person’s medical history is generally normal. For people who have the disease in an internal organ, the symptoms will differ based on which organ is affected. For instance, if synovial sarcoma affects the prostate, it can cause difficulty in urinating. If it affects the lungs, symptoms similar to pneumonia, chest pain, or even blood clot in the lung can occur.

It’s usually challenging to identify synovial sarcoma through clinical examination. However, if a previously healthy young person shows up with a hard lump in their arm, leg, or elsewhere, doctors should consider the possibility of synovial sarcoma.

Testing for Synovial Cell Sarcoma

If you’re being screened for synovial sarcoma (SS), a type of cancer, there are several tests doctors might consider. Interestingly, standard lab tests often yield normal results even when these tumors originate from unusual organs. For instance, even if the SS is affecting the prostate, the prostate-specific antigen (PSA) — a test usually used to measure prostate health — may still show normal results.

One key method of diagnosing SS involves carrying out a biopsy of the mass, which involves taking a small sample of the mass for testing. This should be carefully planned and executed by a team of bone and muscle (musculoskeletal) doctors and interventional radiologists. This procedure could also be done by an experienced surgeon, preferably someone with orthopedic training. It’s generally preferred that the same person who performed the biopsy also carries out the removal of the tumor, if needed.

SS in the retroperitoneal area (a space in the abdomen) is typically diagnosed with a core needle biopsy. In cases where enough sample cannot be obtained through this method, a specialist might opt to perform surgery to remove the mass for testing.

Imaging tests, like computed tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET) scans could provide helpful information. CT scans typically show a clearly defined mass, often with tiny and peripheral calcifications (abnormal calcium deposits). A CT scan of the chest is also necessary to determine the stage of the disease.

MRI is another helpful tool in detecting and determining the stage of synovial sarcoma. Here’s what you might expect from this test:
– T1-weighted images tend to appear dark, while T2-weighted images are bright.
– T2-weighted images may show hypo-, iso-, or hyperintense fat areas. Hyperintense areas indicate bleeding.
– Smaller lesions (less than 5 cm) are usually found on the periphery and generally look benign (have smooth contours, are non-infiltrative, and have homogeneous characteristics)
– Certain MRI sequences with a contrast agent (gadolinium) can help identify primary cystic synovial sarcoma by highlighting the solid node-like enhancing component. This can help differentiate it from a joint cyst and blood clot.

An MRI can also highlight aggressive tumor characteristics, such as the involvement of nearby bones, the enclosure of blood vessels and nerves, and the invasion of muscle tissue. This imaging test is also the best way to determine whether the tumor can be surgically removed. PET/CT scans are usually performed to rule out that the disease has spread to other parts of the body.

Treatment Options for Synovial Cell Sarcoma

Synovial sarcoma is a type of cancer that can be found in different stages. Depending on the stage you’re in when you’re diagnosed, your treatment will vary. If the sarcoma is found in one place, the goal is to completely remove it through surgery. This surgery is done so that no cancer is visible under a microscope. However, in some situations, the sarcoma may have spread and can’t be entirely removed with surgery.

For children, a treatment called neoadjuvant chemotherapy is often used before surgery. However, this approach is a topic of debate when it comes to adults with synovial sarcoma.

If the sarcoma is advanced and has spread to other areas of the body and cannot be entirely removed with surgery, the treatment aims to ease symptoms and extend life rather than cure the disease. Treatment in these cases could involve chemotherapy drugs that target specific parts of cancer cells, drugs that inhibit the action of a protein involved in cancer growth, or participation in a clinical trial to test new treatments.

What else can Synovial Cell Sarcoma be?

On a medical level, different types of tumors can have similar symptoms to synovial sarcoma (SS), so doctors need to look carefully to make the right diagnosis. These include malignant peripheral nerve sheath tumors (MPNST), solitary fibrous tumors (SFT), small blue round cell tumors (SBRCT), and fibrosarcoma.

Here’s more detail:

1. MPNST can look like a particular type of SS (monophasic synovial sarcoma), especially if the SS starts around a nerve. Clues to this being MPNST rather than SS include:
   • The patient already has a condition where nerve tumors develop.
   • The tumor has a complex pattern and unusual cells.
   • There is a slight positive signal for a particular protein (CD-34) – this is usually not seen in SS.
   • Two other proteins (CK-7 and CK-19) do not show up – in SS, often one or both of these will be detected.
2. Ewing Sarcoma/Primitive Neuroectodermal Tumors (PNETs) can also look like SS. If these are suspected, more specific tests will be run to confirm this.
3. ES tumors may express the CD34 protein which is not seen in SS. They also show a pattern of other proteins that differ from SS.
4. SFT tumors have high levels of CD34 and another protein, STAT6 – these are rarely seen in SS.
5. Dermatofibrosarcoma protuberans express CD34 and lack a specific protein. This differentiates them from SS.
6. Gastrointestinal stromal tumor (GIST) sometimes have similar characteristics to SS when found in the gastrointestinal tract. However, they usually express a specific protein, DOG-1, rarely seen in SS.
7. Infantile Fibrosarcoma, common in the first two years of life, does not express a specific protein. This distinguishes them from SS.
8. Spindle cell Rhabdomyosarcoma and Leiomyosarcoma show a certain protein pattern, which are not seen in SS.

Knowing these differences is crucial for correctly diagnosing and treating these diseases.

Surgical Treatment of Synovial Cell Sarcoma

For people diagnosed with synovial sarcoma who have localized disease or cancer that hasn’t spread, the common treatment is limb-sparing surgery. This allows the patient to keep their limbs as amputation or cutting of the limbs is seldom done and reserved only for cases where saving the limb is not possible.

The goal of the surgery is to remove the entire tumor along with a surrounding band of normal tissue of at least 1 to 2 cm. This is to ensure that no cancer cells are left behind.

However, if the tumor has not affected certain layers of connective tissue known as fascia, then the distance of the tumor from the fascia doesn’t matter, as long as the fascia itself is cancer-free. This is considered as an acceptable margin, or safe zone.

If the tumor is less than 5 cm in size, a surgical removal of the tumor, along with a 1-2 cm margin of normal tissue, is considered sufficient. This method is called “wide local resection”.

What to expect with Synovial Cell Sarcoma

Synovial sarcoma is a highly aggressive cancer with a grim prognosis, meaning the outlook is often not promising. It’s classified as a high-grade cancer, indicating it’s typically severe and progresses quickly. Adult patients can normally expect a survival rate of 50 to 60% over five years, while the chance to live this long without the cancer spreading varies from 40 to 60%.

However, the European Pediatric Soft Tissue Sarcoma Study Group revealed a significantly higher survival rate of 90% for children treated over a duration of five years.

Several factors determine how the disease prognosis might fare:

1. Age – Younger patients tend to have a better prognosis.
2. Tumor size – A smaller tumor size could mean better outcomes.
3. Tumor location – Synovial sarcoma that starts in the extremities (arms or legs) usually brings a better prognosis.
4. Perioperative Radiotherapy (a treatment technique that uses high-energy radiation) – This is associated with a better prognosis.
5. The presence of bone invasion or invasion of blood vessels and nerves by the tumor is commonly associated with poor outcomes.
6. Unplanned resections (incomplete surgical removals of the tumor) too are generally correlated with poor outcomes.

Possible Complications When Diagnosed with Synovial Cell Sarcoma

A tumor developing in the body can cause a variety of complications due to the “mass effect”. This effect can put pressure on the surrounding areas, which can lead to different issues. Synovial sarcoma, a type of cancer, rarely spreads to the brain, but if it does, it can cause seizures and other nerve-related complications. In addition, blood clots can form because of the pressure generated by the tumor or simply due to its presence in the body.

Chemotherapy, a common treatment for tumors, has its own set of complications. These may include the weakening of the immune system, hair loss, feeling nauseous, vomiting, and dysgeusia, a condition that affects the sense of taste.

Additionally, different types of drugs used during chemotherapy can produce specific adverse effects:

• Anthracycline – could lead to heart-related complications
• Ifosfamide – could result in nerve and kidney damage
• Pazopanib – could also cause heart and liver damage
• Trabectedin – could result in complications related to the heart, liver, and bone marrow, the latter being known as myelotoxicity

Hence, all healthcare providers must be vigilant about the potential side effects brought about by various chemotherapy treatments.

Preventing Synovial Cell Sarcoma

Synovial sarcoma is a rare and aggressive type of cancer that’s more often seen in children and young adults. Because of its severity and the age of those it affects, it’s important that parents or guardians are fully engaged in the process of managing the disease. This includes understanding the need for treatment options like surgery and radiotherapy (a type of cancer treatment that uses high energy waves to kill cancer cells), as these methods have shown to be crucial in treating this cancer.

However, this illness has been known to resist many treatments, which makes it difficult for medical professionals to manage. Therefore, it’s important to educate both patients and their guardians about the disease, its treatment options, and the key role of different methods, especially surgical removal and radiotherapy.

Before deciding on treatment for synovial sarcoma, it’s crucial that patients, parents, and guardians understand both the benefits and drawbacks of other treatment options, such as chemotherapy before (neoadjuvant) or after (adjuvant) surgery. The decision about which treatment to pursue should only be made after reaching an agreement with the parents or guardians.

Lastly, if there are any clinical trials (research studies that test new treatments to see if they’re safe, effective, and possibly better than the existing treatments) available at your hospital or nearby, patients and their families should consider those opportunities. Such trials can potentially provide new and effective treatments for this challenging disease.